Merges values from alternative config file locations into the config. This allows to overwrite values given from the config provided with the module. It searches for config in the following places. * /etc/tapper.cfg * $ENV{HOME}/.tapper/tapper.cfg * filename given in $ENV{TAPPER_CONFIG_FILE}

Depending on environment variables a context of life, test, or development is derived. Default is live. If HARNESS_ACTIVE is set the context is test, if TAPPER_DEVELOPMENT is set to 1 the context is development.

This context is used for creating the final config. Inside the config all keys under development or test are merged up into the main level. Therefore usually there you put special values overriding defaults.

When the environment variable TAPPERDBMS is set to postgresql (or mysql) then the config values for database.TestrunDB are overwritten by the values <database.by_TAPPERDBMS.postgresql.TestrunDB> respectively.

This introduces a backwards compatible way of using another DBMS with Tapper, in particular PostgreSQL.

These special entries are prepared after the default and context merges.